Summary: Delimiting the Power of Bounded Size Synchronization
Objects
(Extended Abstract)
Yehuda Afek Gideon Stupp
Department of Computer Science Department of Computer Science
Tel­Aviv University Tel­Aviv University
Israel 69978 Israel 69978
Abstract
Theoretically, various shared synchronization objects,
such as compare&swap and arbitrary read­modify­write
registers, are universal [10, 20]. That is, any sequentially
specified task can be solved in a concurrent system that
supports these objects and a large enough number of
shared read/write registers. Are these objects indeed
almighty? Or, are there other considerations that have
to be kept in mind when analyzing their computation
power. In this paper we show that progressively larger
objects of these types are more powerful (larger in the
number of different values they can hold). This provides
a refinement of Herlihy's hierarchy.